public class RemDup{

public static void main(String[] args){
	System.out.println(process(args[0]));
	System.out.println("" + (int)Character.MAX_VALUE);
}


public static String process(String input){
	if(null == input || input.length() <= 0)
		return null;

	int[][] keyMap = new int[Character.MAX_VALUE][2];
	for(int i=0; i<Character.MAX_VALUE; i++)
		keyMap[i][0] = -1;

	StringBuffer buffer = new StringBuffer();
	for(int i =0; i<input.length(); i++){
		char ch = input.charAt(i);
		if(keyMap[ch][0] == -1){
			keyMap[ch][0] = ch;
			keyMap[ch][1] = 1;
			buffer.append(ch);
		} else {
			keyMap[ch][1] = keyMap[ch][1]+1;
	
		}
	}
	return buffer.toString();

}


}